Researchers believe the Osedax genus may be responsible for dissolving bone before they became fossils, which may have affected the fossil record

Researchers from the University of Leeds have discovered a type of zombie-like worm in the Mediterranean, which may be a clue as to how this bone-eating worm affects fossil records.

The zombie worm, which is of the Osedax genus, does not have a mouth or gut, but consumes bone by growing root-like tissues. These tissues dissolve the bone as they grow. The Osedax were first discovered alive in Monterey Bay, California in 2002, where they were feeding on the bones of a gray whale. Ever since, researchers have wondered how these creatures may have affected fossil records.

But this is no easy task. Learning when and where the Osedax evolved has been a challenge because they are soft-bodied and do not preserve as fossils. Yet understanding the Osedax could provide more insight into lost parts of the fossil record due to these worms eating the bones before they could become fossils.

The Osedax may not leave fossils behind, but they do leave their bulb-shaped cavities that they form in a bone. This has allowed Nicholas Higgs, study leader and University of Leeds researcher, to trace their beginnings. Last year, Higgs traveled to the Mediterranean and used micro-CT scanning technology to find traces of the Osedax.

Now, the bulb-shaped cavities have been found in a 3-million-year-old fossil whale bone from Tuscany, Italy. This is the first time the Osedax have been found in this region, and leads researchers to believe that the Osedax were widespread throughout the world's oceans millions of years ago.

According to Higgs, the Mediterranean dried up nearly six million years ago, and about half a million years later, it re-flooded from the Atlantic.

"So finding out that Osedax were feeding on this whale bone three million years ago tell us that their ancestors must have also been living in the Atlantic as well, because the Mediterranean was re-colonized 5.5 million years ago from the Atlantic. There are 20 different species in Monterey, California alone, so it's almost certain there are many more out there. If Osedax were living in the Mediterranean three million years ago, there's no reason why they aren't living there now."